An electron beam welding device is known which consists of an electron beam gun, high-voltage cable, high-voltage power source, low-voltage power source and low-voltage power cable or storage battery (Electron Beam Welder for Space, F. R. Shollhammer, Hamilton Standard Division of United Aircraft Corporation, 6th National Symposium on Materials for Space Vehicle Use, Nov. 18, 19, 20, 1963). Such a device cannot be used for performance of repair-mounting work in space because of the difficulty of manipulating the massive (120 lb=54 kg) EB gun by the operator in a spacesuit, i.e. because there is no mobile tool for manual work performance and also because of the higher risk involved when using the high-voltage cable and higher anode power voltage (80 kV) of the EB gun.
A device for electron beam welding at earth surface conditions is known which consists of an EB gun powered by low-voltage and high-voltage power sources connected in series. The EB gun and the high-voltage power source are placed in a vacuum chamber, whereas the low-voltage source is located outside the chamber, and these power sources are connected by a low-voltage cable (Chvertko A. l., Nazarenko O. K., Svyatskii A. M., Nekrasov A. l., Equipment for EB Welding, Kiev, "Naukova Dumka," 1973, p. 185). Such a device cannot be used to perform the repair-mounting work in space, in view of its limited mobility, since part of the equipment is located in a compartment which cannot be depressurized, and also because it lacks a tool for performing manual work.
A device for EB welding is known which comprises an electron beam gun and high-voltage power source which are rigidly fastened to each other (Chvertko A. l., Nazarenko O. K., Svyatskii A. M., Nekrasov A. l., Equipment for EB Welding, Kiev, "Naukova Dumka," 1973, p. 360, FIG. 286). However, such a device was used only as a stationary component of equipment which operated in an automatic mode.
Self-sufficient devices for investigation of EB welding under the conditions of space are also known to incorporate EB guns, high-voltage and low-voltage power sources designed as one module, and also a storage battery. These devices were permanently mounted inside the pumped-down compartments of the Soyuz-6 and Skylab space vehicles and functioned in the automatic mode with remote control from a panel which was located in the living quarters (Chvertko A. l., Nazarenko O. K., Svyatskii A. M., Nekrasov A. l., Equipment for EB Welding, Kiev, "Naukova Dumka," 1973, pp. 360-361; Lienay H. G., Lowry I. F., Hassan S. V., Battery Powered Electron Beam Device, "Welding & Metal Fabrication," 1967, 35, No. 12, pp. 472-478). These devices cannot be used for performing repair work because they are cumbersome and cannot be manipulated by the astronaut-operator.
A device for manual EB welding in space is known (Chvertko A. I., Nazarenko O. K., Svyatskii A. M., Nekrasov A. l., Equipment for Electron Beam Welding, Kiev, "Naukova Dumka," 1973, p. 357, FIG. 280). This device accommodates the low-voltage (inverter) and high-voltage (stepping-up transformer, rectifier) power sources designed as one module and a mobile EB gun with a high-voltage power cable. These devices, however, do not include engineering to make them suitable for safe and convenient operation during EVA.
Also known are the gun-type tools for electron beam welding under vacuum, comprising an EB gun with a handle and high-voltage cable, which are moved and controlled by an operator in a spacesuit (Chvertko A. l., Nazarenko O. K., Svyatskii A. M., Nekrasov A. l., Equipment for EB Welding, Kiev, "Naukova Dumka," 1973, p. 358; Zagrebelnii A. A., et al., A Unit for Manual EB Welding, E.O. Paton Electric Welding Institute of the Ac. of Scs. of Ukr.SSR, Newsletter 31 (998), 1976). However, the mobile flexible high-voltage cable which is part of these tools is a less reliable element and a source of potential danger to the operator. Also, in these tools the weight of the gun is shifted forward and accounts for the largest share of the total tool weight, i.e. the moment of inertia of the handtool relative to the handle is high, which makes it difficult for the operator, especially under zero gravity, to perform the precise small displacements which are necessary in welding.
Stationary mechanisms for filler feed are known to be used in electron beam welding (Chvertko A. l., Nazarenko O. K., Svyatskii A. M., Nekrasov A. l., Equipment for EB Welding, Kiev, "Naukova Dumka," 973, pp. 62-63, FIG. 32). Such filler feed mechanisms cannot be used in handtools for EB welding in space because of the relatively large dimensions and rigid fastening of these mechanisms relative to the butt being welded.
Additional focusing systems of EB guns are known to be used for forming the electron beam (Chvertko A. l., Nazarenko O. K., Svyatskii A. M., Nekrasov A. l., Equipment for EB Welding, Kiev, "Naukova Dumka," 1973, p.121-129, FIGS. 52, 76, 78, 79, 80). Such focusing systems cannot be used in handtools for electron beam welding in space because of their relatively large overall dimensions, high power consumption and cooling system requirements.
A device for melting materials in space is known which contains a crucible with the molten material and heat source (U.S. Pat. No. 3,647,924). This device addresses the issues of structural strength and rigidity, but does not provide any means for containing the melt under zero gravity which makes it impossible for an operator in a spacesuit to use this device.